1. Field of the Invention
The present specification generally relates to drill cuttings conveyance systems and, more particularly, to systems and methods for conveying drill cuttings generated from oil and natural gas drilling operations.
2. Description of Related Art
Drill fluid generally includes one or more of hydrocarbons, water, salt, and other chemicals or substances and is widely used in oil and natural gas drilling operations. Drill fluid may provide subsurface pressure that aids in the prevention of underground fluids from entering the borehole, lubricates and cools the drill bit, and carries ground-up earth (which may be generally referred to herein as drill cuttings solids), in suspension, back to the surface so that it does not interfere with drilling operations. Typically, drill fluid is injected from the surface during the drilling process down through an annular channel within the drill string. The drill fluid then exits the drill string through nozzles or apertures in the drill bit where it thereafter returns to the surface in the area between the drill string and the walls of the borehole, carrying with it the drill cuttings solids so that they are removed from the borehole.
It may be desirable to reuse the drill fluid for further drilling operations after it has been recovered from the borehole. In order to do so, and in order to facilitate the disposal or recycling of the drill cuttings solids, the solids generally must be separated, or substantially separated, from the drill fluid. The drill cuttings containing drill fluids and solids, once it arrives at the surface, generally is passed over one or more shaker screens, also called rig shakers or shale shakers, that may vibrate to aid in the separation of the solids from the drill fluid. Generally, as drill cuttings pass over the shaker screens, the drill fluid passes through the screens, while the solids are caught by the screens and directed to a collection or storage area. Often, however, the use of shaker screens alone is insufficient to remove enough drill fluid from the solids to allow for the solids' disposal. Therefore, additional processing of the drill cuttings may be necessary to further remove drill fluid therefrom. Processing equipment often includes a hydrocyclone, centrifuge, or other similar equipment that generally is operable to process the drill cuttings for further removal of drill fluid.
A number of augers often are used to channel drill cuttings to various stages of conventional systems. Augers generally are rigid, fixed in length, and limited to the degree they can be positioned at an incline. Thus, augers tend to require a large amount of space to direct drill cuttings through or to a processing system. Further, augers may be susceptible to clogging with drill cuttings having a high viscosity and, conversely, can have difficulty in directing, particularly at an incline, drill cuttings having a low viscosity. For these reasons, and given the tendency of drill cuttings solids to settle, augers generally are not configured to passively receive (i.e., receive while not in operation) drill cuttings. As a result, augers tend to be in constant operation in an attempt to prevent such settling and blockages. Also, due to the large amount of surface area on the flights of an auger, drill cuttings constantly are wearing down or eroding the auger, rendering it to what may be a short operating life.
In addition, conventional systems and methods often rely on the use of heavy machinery, such as excavators, to handle or transport drill cuttings at various stages thereof. For instance, excavators commonly are used to transfer drill cuttings from a tank or pit to a processing system for removal of drill fluid. Once the drill cuttings have been processed and drill fluid has been substantially removed therefrom, the remaining solids of the drill cuttings often are directed into another auger, holding tank, or pit until they ultimately are transferred once again with the aid of an excavator to a vehicle or a transportable container for transport. The use of heavy machinery to transfer drill cuttings from one place to another generally is inefficient as such transfers often are inconsistent and fail to provide a continuous conveyance of drill cuttings to the processing equipment. In addition, having heavy equipment, such as excavators, on site is a costly expense to drill operators and may be hazardous to the working crew.